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View Full Version : Jetting question!


300exracer
06-25-2003, 03:52 PM
Ok well i have a 300ex with a 128 main jet and thats all we did to it. It seems to run good but back fires on de accelaration and i checked and there is no exhuast leak so is that normal when it back fires!:confused: :confused: please help
300exracer
06-25-2003, 04:13 PM
anyone?
cals400ex
06-25-2003, 04:57 PM
what did white brothers suggest for the main jet? also, you will probally have to go up one more size than they say because of the K&N filter. is your bike jetted yet? i am not sure on 300ex's but on 400ex's, the pilot jet is a little small so we usually go from the stock 38 pilot to a 40 or a 42. also, many times we will go from the stock needle position (3rd notch) to the 4th notch (one step richer). jetting is critical for performance. also, what color is your plug?